If you lost your Sprint cell phone, don't come knocking on the door of Wayne Dobson, 58.

In the two years that Dobson has lived in his one-story home with his wife, five people--all missing their Sprint cell phones--have come knocking on his door, demanding that he return their handsets.

If a GPS tracker for your lost cell phone leads you to Dobson's home, you'll find a sign outside his door in North Las Vegas, Nev., that reads, "No lost cell phones!! This location gives a false 'phone locator' position due to a cell tower behind this home. Please contact the North Las Vegas Police and file a report."

"I put it up because there seems to be no end to this," he said.

On Dec. 18, four men who Dobson described as "young" pounded on his door at around 2:30 a.m., shouting for him to return their phone. One of the men had a tablet with a tracking application, pointing to Dobson's home.

"I understand why people are upset. These are $300 or $500 devices," Dobson said. "I'm worrying about someone showing up in an agitated state, are drinking, and if that one person has a weapon perhaps. This is Las Vegas."

He told the men repeatedly that he didn't have their cell phone and they eventually went away.

"When those things happen, you don't go back to sleep," Dobson said. "You wonder if they are going to throw a rock in the window, or spray paint on my wall."

It got so bad that on many weekends, he sleeps in the big chair near the door, as first reported by the Las Vegas Review-Journal.

"I never know when this is going to happen. I can't sleep comfortably any more. I think, what's going to happen next? It's a very disturbing problem," Dobson said.

The problem is so vexing that he said he has reached out to his city council commissioners, Sprint and the chief of police. Sprint hasn't responded to him yet.

Sprint said the company is looking into the matter.

Dobson had finally had enough on Dec. 30 around 4 a.m., when police showed up at his home in response to a 911 call. After first being startled by noise and a flashlight outside one of his windows, a police officer demanded that Dobson come outside and he was searched for weapons.

He later learned a police dispatcher received a 911 call but was unable to get the address from the caller. A police system tracker had led cops to Dobson's home.

It was the fourth time police had come knocking on his door. Two of the visits were prompted by people who had called police trying to find a lost cell phone. In the other two cases, police mistakenly showed up at his door in response to a 911 call.

North Las Vegas police spokeswoman Chrissie Coon told the Review Journal that the accuracy of tracking locations based on cell phone location is "not a perfect technology" and the police department only infrequently dispatches police via that method.

The Review-Journal reports that the problem could be related to the cell phone tower that is about 300 to 400 yards from Dobson's home, but cell phone technology experts John B. Minor and Ben Levitan told the Review-Journal that they think the problem has to do with Sprint's switchboard.